In manufacturing industries in which a product lifecycle becomes short and the market change is vigorous, it is important to organize the production planning work capable of quickly meeting a customer's request.
In the production planning work, the production plan of specifying when and where each product is produced and how many products are produced is prepared at intervals of months or weeks, and this result is provided for the work in which the material procurement or manufacturing instruction is performed.
However, in the production planning work, in the case where even in the same product, a change occurs in multiple input information, or in the case where a manufacturing machine is shared by multiple products, since it is uncertain which input information influences which production planning result, for example, as disclosed in Japanese Patent Application No. JP-A-11-282824 (“patent document 1”), operations of (1) calculation of a manufacturing (production) availability number, (2) comparison of the previous/current manufacturing (production) availability numbers, and (3) recalculation of a manufacturing (production) availability number after input information correction have been repeatedly performed.
As disclosed in the patent document 1, since the operations of (1), (2) and (3) are repeated until a satisfactory production plan is obtained, it takes much time, and a practical production planning preparation work can not be performed. In particular, there has been a serious problem in a production line in which customer demand is frequently changed, a change in yield of the production line is vigorous, and a manufacturing process routing is complicated.